Tents having frame members which are assembled from a series of rods carried in the pivotal sockets of a number of hubs are not new per se. A number of United States and foreign patents have issued on such generic structures. One of those patents which, it is believed, represents the closest prior art to the present invention is U.S. Pat. No. 3,766,932. That patent discloses a three-dimensional collapsible structure formed by an array of bar-like elements each pivotally connected at its ends to one or more other such elements. The primary object of that disclosure seems to be true collapsibility; however, if the description of the invention is followed closely with the drawings, it would appear that the object is unattainable and the structure depicted in FIGS. 1 and 2 of the patent cannot be collapsed into the package shown in FIG. 8. Furthermore, the perametric rods forming the bottom portion of the tent frame make contact with the ground at spaced apart points, leaving elevated triangular shaped spaces to be filed by angulation of the tent floor, wasting floor space. Because the frame is apparently intended to be totally self-supporting without the tent skin, the disclosure makes no reference as to how the skin is applied or supported. Because the skin is not a structural element, the frame portion is necessarily more complex than it needs to be because it is apparently made to be self-supporting without the use of compression members to achieve bending and self-support, as in the present invention.
The patents discussed in the specification of the above mentioned patent, including the British Patent 1,009,371, are relevant to the instant disclosure but do not anticipate its simplicity, ease of operation and structural integrity. Other U.S. patents which disclose frames of the same general type are: Nos. 3,502,091; 2,716,993; 2,781,767; 3,059,658 and 3,197,927.
As seen from the complexity and doubtful utility of the prior art, it is the primary object of the present invention to provide a tent structure which includes a free-standing frame and a structurally cooperative floor which can be collapsed into a compact package whose length is equivalent to the length of the individual compression rods forming the structure.
A second object of the invention is to provide one species of the generic tent frame structure which has the optimum volume characteristics of a substantial hemisphere.
A still further object of the invention is to generically provide a structure whose floor plan can vary but the constance of the principal design characteristic of alternate level reverse articulation will always produce a structure which will be collapsible in the manner of the first objective.
Another object of the invention is to provide a structure conforming to geometries based on polyhedra which are not limited to 2n sides, but on the other hand may be triangles or pentagons to provide flexibility of design.